不同品种大豆分离蛋白体外消化产物的结构特性

Structural Characteristics of in Vitro Digested Products of Different Soybean Protein Isolates

以我国5种大豆分离蛋白(SPI)为基础原料,运用多种蛋白分析检测手段,研究这5种大豆分离蛋白结构对体外模拟消化特性的影响。结果表明:大豆分离蛋白及消化产物的红外光谱、拉曼光谱分析二级结构元素含量变化规律基本一致,α-螺旋结构、β-折叠结构与DH呈现一定相关性。5种大豆分离蛋白样品及其消化产物的酪氨酸残基趋向于“暴露式”,随着消化时间的延长,λmax整体上增大,拉曼色氨酸侧链归属谱带强度随消化时间的延长逐渐降低,表明色氨酸残基趋向于亲水性微环境。5种大豆分离蛋白经连续5h的体外模拟消化试验,水解度DH随着消化时间的延长而增加,当消化时间超过1h后,DH的增加速度减慢,而在相同条件下不同样品DH存在差异性。

In this experiment,five kinds of soy protein isolate as raw materials,using a variety of protein analysis and detection methods,study in structure changes of in vitro digestion process soy protein isolate.Fitting FT-IR and Raman spectroscopy result of soy protein isolate and digestion products showed that the changes of content of the secondary structural elements were basically the same,a negative correlation was found between DH and α-helix,β-sheet content.Tyrosine residues of soybean protein isolate and digestion products tend to be“exposed”.The increasing λmax with digestive time and decreased Raman band intensity of tryptophan suggested that tryptophan residues tend to hydrophilic microenvironment.Five different varieties of soy protein isolate after 5 h of continuous digestion in vitro experiments,the degree of hydrolysis increases with time,but after 1h after digestion,the growth rate of DH slowed down and under the same conditions,DH differences between different samples.